Small Craft Advisory 522, NWS Anchorage, AK

AREA FORECAST DISCUSSION
SOUTHCENTRAL AND SOUTHWEST ALASKA
200 PM AKDT MON JUL 1 2008

.MODEL DISCUSSION...
MODELS IN FAIR AGREEMENT IN THE SHORT TERM AFTER EARLIER DIFFICULTIES
RESOLVING THE LOW NEAR THE EASTERN ALEUTIANS. THE PROBLEMS THAT ARISE
BEYOND 60 HOURS CAN BE PINPOINTED TO LARGE DISCREPANCIES IN THE UPPER
LEVELS...PARTICULARLY THE TIMING AND STRENGTH OF THE SHORT WAVES
ROTATING AROUND THE LONG WAVE TROUGH LOCATED IN THE CENTRAL BERING
SEA LATER IN THE WEEK. THE CONSENSUS SOLUTION FROM ALL THE MODELS
AVAILABLE IS THAT THE LONG WAVE TROUGH WILL BECOME ORIENTED NW TO SE
THURSDAY WITH A STRONG SHORT WAVE MOVING OUT OF THE NORTH PACIFIC
HELPING SWING THE MAIN CIRCULATION TO THE SOUTHERN GULF OVER THE
WEEKEND. UNTIL THE MODELS GET A BETTER HANDLE ON THE TIMING OF THIS
TRANSITION...THE CONFIDENCE IN THE LOCATION AND STRENGTH OF THE
SURFACE FEATURES WILL REMAIN LOW BEYOND 60 HOURS. A BLEND OF THE
INHERITED FORECAST AND 12Z GFS WAS USED FOR THE FIRST 60 HOURS AND
THEN NO CHANGES WERE MADE IN THE EXTENDED.

.ANALYSIS AND UPPER LEVELS...
ONE UPPER LOW LOCATED OVER THE ALASKA RANGE NEAR THE ALASKA/CANADA
BORDER ON ITS WAY TO BECOMING CUTOFF FROM THE MAIN CIRCULATION IN THE
NORTHERN YUKON TERRITORY. SURFACE ANALYSIS SHOWS A WEAK LOW EXTENDING
SOUTHWEST TOWARD THE COPPER RIVER BASIN WHICH WILL HELP INITIATE
CONVECTION THIS AFTERNOON IN THAT AREA. UPPER LEVEL RIDGE AND SURFACE
HIGH PRESSURE BUILDING OVER SOUTH CENTRAL ALASKA PROVIDING FAIR
WEATHER FOR A LARGE PORTION OF OUR FORECAST DOMAIN. A SECOND UPPER
LOW LOCATED JUST WEST OF DUTCH HARBOR WITH THE SURFACE REFLECTION
LOCATED JUST TO THE NORTHWEST OF DUTCH AT 989 MB. THE FRONTAL
BOUNDARY ASSOCIATED WITH THIS SYSTEM EXTENDS SOUTH ACROSS THE WESTERN
ALASKA PENINSULA INTO THE NORTH PACIFIC. WEAK HIGH PRESSURE IS IN
CONTROL OF THE WESTERN BERING SEA.

.SHORT TERM FORECAST...
SOUTH CENTRAL ALASKA...THE DEPARTING UPPER LOW NEAR THE BORDER WILL
CONTINUE TO MOVE INTO THE YUKON TERRITORY TONIGHT. IN THE MEAN
TIME...ENOUGH INSTABILITY WILL BE PRESENT IN THE COPPER RIVER BASIN
AS WELL AS THE NORTHERN SUSITNA VALLEY NEAR THE PARK FOR THUNDERSTORM
INITIATION THIS AFTERNOON. VISIBLE SATELLITE INDICATING BUILDING
CUMULUS CLOUDS AND PAGK NOW REPORTING CB IN ALL QUADS. EXPECT THIS TO
BE THE LAST AFTERNOON FOR THUNDERSTORMS AS THE RIDGE MOVES OVER THE
COPPER RIVER AND SUPPRESSES DEVELOPMENT BEYOND SOME ISOLATED MOUNTAIN
SHOWERS. STABLE AIR WILL PERSIST OVER THE AREA UNTIL FRIDAY WHEN THE
THERMAL TROUGH BUILDS AND EASTERLY WAVES BRING SOME ADDED INSTABILITY
BY THE WEEKEND.

ELSEWHERE...CLEAR SKIES WILL PREVAIL UNTIL THE NEXT SYSTEM MOVES OUT
OF THE NORTH PACIFIC. HIGH CLOUDS WILL MOVE INLAND WEDNESDAY NIGHT AS
RAIN RETURNS TO KODIAK AND EVENTUALLY THE REST OF THE GULF COAST
FRIDAY. THE SOUTH CENTRAL INTERIOR WILL STAY RELATIVELY DRY THROUGH
THE WEEK BESIDES THE STRAY SHOWER HERE AND THERE.

FIRE WEATHER HAZARDS WILL BE LIMITED TO LOW RELATIVE HUMIDITIES. VERY
LITTLE WIND IS EXPECTED THIS WEEK OUTSIDE OF THE AFTERNOON SEA
BREEZES ALONG COASTAL SECTIONS. INTERIOR WINDS WILL REMAIN 15 MPH OR
LESS. THE RH WILL DROP TO NEAR 15-25 PERCENT IN THE WARMEST AREAS
INLAND AS TEMPERATURES RISE INTO THE LOWER 70S THE NEXT COUPLE OF
DAYS. WILL HAVE TO WATCH FOR THE POTENTIAL FOR RH TO DROP BELOW 15
PERCENT BUT DO NOT ANTICIPATE THAT AT THIS POINT.

SOUTHWEST ALASKA...
A STRONG FRONT IS CURRENTLY LOCATED JUST WEST OF COLD BAY. RAIN IS
FALLING ALONG AND AHEAD OF THIS FRONT BUT IS HAVING A HARD TIME
MOVING INLAND. SO FAR...RAIN HAS BEEN LIMITED TO THE BRISTOL BAY AND
KUSKOKWIM DELTA COASTLINE. THE MAIN STORY WITH THIS FRONT IS THE
WINDS. SOUTHEASTERLY GUSTS HAVE BEEN AS HIGH AS 60 MPH IN COLD BAY
WITH SEVERAL LOCATIONS ON THE ALASKA PENINSULA REPORTING WINDS 35 TO
50 MPH. THE HIGH PRESSURE BUILDING OVER SOUTH CENTRAL WILL IMPEDE ITS
EASTWARD PROGRESSION BUT STILL EXPECT WINDS TO INCREASE IN PUBLIC
ZONE 161...ESPECIALLY THROUGH CHANNELED TERRAIN AND ALONG THE WESTERN
CAPES. THE BEST CHANCE OF RAIN WILL BE LATER THIS WEEK WHEN A SHORT
WAVE MOVES OUT OF THE NPAC AND HELPS PUSH THE MOISTURE FURTHER
INLAND. UNTIL THEN...ONLY ISOLATED SHOWERS ARE EXPECTED OVER THE
INTERIOR WITH AREAS OF STRATUS AND PATCHY FOG DEVELOPING OVERNIGHT.

NO FIRE WEATHER CONCERNS IN THE WESTERN DOMAIN AS CONDITIONS WILL
REMAIN WET. NO THUNDERSTORM DEVELOPMENT IS EXPECTED THROUGH FRIDAY.

.AER/ALU...WATCH/WARNING SUMMARY
PUBLIC...NONE.
MARINE...GALE 150 155 160 180
FIRE WEATHER...NONE.

AB JUN 08